rust-clippy/tests/ui/unnecessary_lazy_eval.rs

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//@aux-build: proc_macros.rs
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#![warn(clippy::unnecessary_lazy_evaluations)]
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#![allow(clippy::redundant_closure)]
#![allow(clippy::bind_instead_of_map)]
#![allow(clippy::map_identity)]
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#![allow(clippy::needless_borrow)]
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#![allow(clippy::unnecessary_literal_unwrap)]
#![allow(clippy::unit_arg)]
#![allow(arithmetic_overflow)]
#![allow(unconditional_panic)]
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use std::ops::Deref;
extern crate proc_macros;
use proc_macros::with_span;
struct Deep(Option<usize>);
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#[derive(Copy, Clone)]
struct SomeStruct {
some_field: usize,
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}
impl SomeStruct {
fn return_some_field(&self) -> usize {
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self.some_field
}
}
fn some_call<T: Default>() -> T {
T::default()
}
struct Issue9427(i32);
impl Drop for Issue9427 {
fn drop(&mut self) {
println!("{}", self.0);
}
}
struct Issue9427FollowUp;
impl Drop for Issue9427FollowUp {
fn drop(&mut self) {
panic!("side effect drop");
}
}
struct Issue10437;
impl Deref for Issue10437 {
type Target = u32;
fn deref(&self) -> &Self::Target {
println!("side effect deref");
&0
}
}
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fn main() {
let astronomers_pi = 10;
let ext_arr: [usize; 1] = [2];
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let ext_str = SomeStruct { some_field: 10 };
let mut opt = Some(42);
let ext_opt = Some(42);
let nested_opt = Some(Some(42));
let nested_tuple_opt = Some(Some((42, 43)));
let cond = true;
// Should lint - Option
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let _ = opt.unwrap_or_else(|| 2);
let _ = opt.unwrap_or_else(|| astronomers_pi);
let _ = opt.unwrap_or_else(|| ext_str.some_field);
let _ = opt.unwrap_or_else(|| ext_arr[0]);
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let _ = opt.and_then(|_| ext_opt);
let _ = opt.or_else(|| ext_opt);
let _ = opt.or_else(|| None);
let _ = opt.get_or_insert_with(|| 2);
let _ = opt.ok_or_else(|| 2);
let _ = nested_tuple_opt.unwrap_or_else(|| Some((1, 2)));
let _ = cond.then(|| astronomers_pi);
let _ = true.then(|| -> _ {});
let _ = true.then(|| {});
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// Should lint - Builtin deref
let r = &1;
let _ = Some(1).unwrap_or_else(|| *r);
let b = Box::new(1);
let _ = Some(1).unwrap_or_else(|| *b);
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// Should lint - Builtin deref through autoderef
let _ = Some(1).as_ref().unwrap_or_else(|| &r);
let _ = Some(1).as_ref().unwrap_or_else(|| &b);
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// Cases when unwrap is not called on a simple variable
let _ = Some(10).unwrap_or_else(|| 2);
let _ = Some(10).and_then(|_| ext_opt);
let _: Option<usize> = None.or_else(|| ext_opt);
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let _ = None.get_or_insert_with(|| 2);
let _: Result<usize, usize> = None.ok_or_else(|| 2);
let _: Option<usize> = None.or_else(|| None);
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let mut deep = Deep(Some(42));
let _ = deep.0.unwrap_or_else(|| 2);
let _ = deep.0.and_then(|_| ext_opt);
let _ = deep.0.or_else(|| None);
let _ = deep.0.get_or_insert_with(|| 2);
let _ = deep.0.ok_or_else(|| 2);
// Should not lint - Option
let _ = opt.unwrap_or_else(|| ext_str.return_some_field());
let _ = nested_opt.unwrap_or_else(|| Some(some_call()));
let _ = nested_tuple_opt.unwrap_or_else(|| Some((some_call(), some_call())));
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let _ = opt.or_else(some_call);
let _ = opt.or_else(|| some_call());
let _: Result<usize, usize> = opt.ok_or_else(|| some_call());
let _: Result<usize, usize> = opt.ok_or_else(some_call);
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let _ = deep.0.get_or_insert_with(|| some_call());
let _ = deep.0.or_else(some_call);
let _ = deep.0.or_else(|| some_call());
let _ = opt.ok_or_else(|| ext_arr[0]);
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let _ = Some(1).unwrap_or_else(|| *Issue10437); // Issue10437 has a deref impl
let _ = Some(1).unwrap_or(*Issue10437);
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let _ = Some(1).as_ref().unwrap_or_else(|| &Issue10437);
let _ = Some(1).as_ref().unwrap_or(&Issue10437);
// Should not lint - bool
let _ = (0 == 1).then(|| Issue9427(0)); // Issue9427 has a significant drop
let _ = false.then(|| Issue9427FollowUp); // Issue9427FollowUp has a significant drop
// should not lint, bind_instead_of_map takes priority
let _ = Some(10).and_then(|idx| Some(ext_arr[idx]));
let _ = Some(10).and_then(|idx| Some(idx));
// should lint, bind_instead_of_map doesn't apply
let _: Option<usize> = None.or_else(|| Some(3));
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let _ = deep.0.or_else(|| Some(3));
let _ = opt.or_else(|| Some(3));
// Should lint - Result
let res: Result<usize, usize> = Err(5);
let res2: Result<usize, SomeStruct> = Err(SomeStruct { some_field: 5 });
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let _ = res2.unwrap_or_else(|_| 2);
let _ = res2.unwrap_or_else(|_| astronomers_pi);
let _ = res2.unwrap_or_else(|_| ext_str.some_field);
// Should not lint - Result
let _ = res.unwrap_or_else(|err| err);
let _ = res.unwrap_or_else(|err| ext_arr[err]);
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let _ = res2.unwrap_or_else(|err| err.some_field);
let _ = res2.unwrap_or_else(|err| err.return_some_field());
let _ = res2.unwrap_or_else(|_| ext_str.return_some_field());
// should not lint, bind_instead_of_map takes priority
let _: Result<usize, usize> = res.and_then(|x| Ok(x));
let _: Result<usize, usize> = res.or_else(|err| Err(err));
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let _: Result<usize, usize> = res.and_then(|_| Ok(2));
let _: Result<usize, usize> = res.and_then(|_| Ok(astronomers_pi));
let _: Result<usize, usize> = res.and_then(|_| Ok(ext_str.some_field));
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let _: Result<usize, usize> = res.or_else(|_| Err(2));
let _: Result<usize, usize> = res.or_else(|_| Err(astronomers_pi));
let _: Result<usize, usize> = res.or_else(|_| Err(ext_str.some_field));
// should lint, bind_instead_of_map doesn't apply
let _: Result<usize, usize> = res.and_then(|_| Err(2));
let _: Result<usize, usize> = res.and_then(|_| Err(astronomers_pi));
let _: Result<usize, usize> = res.and_then(|_| Err(ext_str.some_field));
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let _: Result<usize, usize> = res.or_else(|_| Ok(2));
let _: Result<usize, usize> = res.or_else(|_| Ok(astronomers_pi));
let _: Result<usize, usize> = res.or_else(|_| Ok(ext_str.some_field));
let _: Result<usize, usize> = res.
// some lines
// some lines
// some lines
// some lines
// some lines
// some lines
or_else(|_| Ok(ext_str.some_field));
// neither bind_instead_of_map nor unnecessary_lazy_eval applies here
let _: Result<usize, usize> = res.and_then(|x| Err(x));
let _: Result<usize, usize> = res.or_else(|err| Ok(err));
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}
#[allow(unused)]
fn issue9485() {
// should not lint, is in proc macro
with_span!(span Some(42).unwrap_or_else(|| 2););
}
fn issue9422(x: usize) -> Option<usize> {
(x >= 5).then(|| x - 5)
// (x >= 5).then_some(x - 5) // clippy suggestion panics
}
fn panicky_arithmetic_ops(x: usize, y: isize) {
#![allow(clippy::identity_op, clippy::eq_op)]
// See comments in `eager_or_lazy.rs` for the rules that this is meant to follow
let _x = false.then(|| i32::MAX + 1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| i32::MAX * 2);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| i32::MAX - 1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| i32::MIN - 1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| (1 + 2 * 3 - 2 / 3 + 9) << 2);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 255u8 << 7);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 255u8 << 8);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 255u8 >> 8);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 255u8 >> x);
let _x = false.then(|| i32::MAX + -1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| -i32::MAX);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| -i32::MIN);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| -y);
let _x = false.then(|| 255 >> -7);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 255 << -1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 1 / 0);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| x << -1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| x << 2);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| x + x);
let _x = false.then(|| x * x);
let _x = false.then(|| x - x);
let _x = false.then(|| x / x);
let _x = false.then(|| x % x);
let _x = false.then(|| x + 1);
let _x = false.then(|| 1 + x);
let _x = false.then(|| x / 0);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| x % 0);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| y / -1);
let _x = false.then(|| 1 / -1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| i32::MIN / -1);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| i32::MIN / x as i32);
let _x = false.then(|| i32::MIN / 0);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 4 / 2);
//~^ ERROR: unnecessary closure used with `bool::then`
let _x = false.then(|| 1 / x);
// const eval doesn't read variables, but floating point math never panics, so we can still emit a
// warning
let f1 = 1.0;
let f2 = 2.0;
let _x = false.then(|| f1 + f2);
//~^ ERROR: unnecessary closure used with `bool::then`
}